Beverage flask



FIG. 1 is a front view of a beverage flask showing my new design;

FIG. 2 is a right side view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a rear view thereof; and,

FIG. 7 is a perspective view thereof.

The broken line showing in the figure drawings are included for the purpose of illustration and form no part of the claimed design. 

CLAIM The ornamental design for a beverage flask, as shown and described. 